If it was fermin for 24 hrs on a stir plate, whether chilly or not, and this was the second step already you should have a nice little pile of cells there to work with. IMO I wouldn't even bother with the extra spep(s) its just a waste of good sugar. However, how do you know when high krausen is achieved ?, you learn your strain and watch it like a hawk. You will know when the yeast begin activity because the top of the culture will change. Either getting more frothy or thicker or just dif will due for now. More importantly than knowing high krausen is to know when activity begins and when it ends. However, high krausen is still high krausen. Even on a stir plate, if you give the yeast what they need, they will still puff up and make a frothy head on top of the starter that signals high krausen, but you don't really need high krausen IMO to accopmplish your goal. You just need healthy cells that will go to work which I think you already have. again IMO.
Hope this helps,
Back to your question here.......I think you can go ahead and pitch that bad boy. Don't even bother adding more starter wort. You've gone through pleanty already. The viable yeast cells are there you just need to get em in the beer before they use up their reserves.